A disk loading device for loading a disk is provided at a information recording/reproducing device, such as a compact disk (hereinafter referred to as “CD”) player, CD drive, digital versatile disk (hereinafter referred to as “DVD”) RON drive, DVD audio player, DVD recorder, or the like, using various types of disk-like recording mediums (hereinafter referred to as “disk”). The mainstream of the construction of the disk loading device is that, when the disk handled by the information recording/reproducing device is placed on a tray that is drawn out from the device in the disk loading device, this tray is moved to the inside of the device, stored therein, and then, automatically clamped by a turntable that rotates the disk, thereby completing the preparation for recording and reproduction.
On the other hand, chances have recently been increasing wherein this type of information recording/reproducing device is installed and used with the state in which the surface of the disk becomes vertical, for space saving. Therefore, the information recording/reproducing device is commonly designed such that it can be used even with the state in which the disk is horizontally placed or with the state in which the disk is vertically placed. In case where the device is installed such that the disk is horizontally placed, the disk is stably placed on the tray, so that there is no problem. However, in case where the device is installed such that the disk is vertically placed, the disk is naturally slipped off from the tray with this state, so that the disk cannot be placed on the tray. Therefore, a projection of some kind is provided at the section of the tray corresponding to the outer periphery of the disk, whereby the disk can beheld by this projection at generally the same relative position with respect to the tray as the case of horizontally placing the disk. By carrying out the loading operation of the disk with this state, the loading operation is performed in the same manner as in the case of horizontally placing the disk. However, in order to stably load the disk in a vertical state with this structure, this projection has to take the shape of overhanging toward the neighborhood of the inside or toward the inside of the outer periphery of the disk.
The overhanging shape does not matter in the case of vertically installing the device. However, in the case of horizontally installing the device, the disk has to be placed as slipped under the projection upon placing the disk on the tray, which means that the disk cannot be placed on the tray with a simple operation. If the disk is erroneously placed on the overhanging section without being slipped under the projection, the disk is not properly loaded on the tray. As a result, not only a proper recording/reproduction cannot be performed by the information recording/reproducing device, but also, in extreme cases, there may arise a case of entailing a fatal result as the information recording/reproducing device, the example of which is that the disk slides with this projection upon rotating the disk to thereby damage the disk, causing the destroy of recording data of a user.
Accordingly, attention is called in an operation manual of the device, or a structure is taken in which this overhanging section can be housed when the device is horizontally installed and used. However, in this measure, whether the above-mentioned fatal result can be avoided or not depends upon the action of the user, thereby entailing a problem that this measure is by no means sufficient.
With respect to this problem, a method has been conventionally proposed wherein the rotation number of the disk is counted after a predetermined time from the start of the rotation upon the start of the rotation of the disk, determines whether the disk is properly loaded to the information recording/reproducing device, and executes an appropriate operation when it is determined to be abnormal, as disclosed in the Reference(Patent Document 1). Since the torque of the motor and the inertia moment of the disk and the rotator of the motor fall within a certain range, the rotation number after the predetermined time from the start of the rotation falls within some fixed range, in case where the disk is properly loaded. In case where the rotation number is outside this range, it is determined that the disk is not properly loaded, so that the operation such as drawing out the tray is executed.
[Patent Document 1] Japanese Unexamined Patent Application No. HEI7-176121